1. Technical Field
The present invention relates to a virtual image display apparatus that presents images formed by an image display device to an observer.
2. Related Art
Various systems have been proposed as optical systems incorporated in virtual image display apparatuses including head mounted displays (hereinafter, referred to as HMDs) attached to heads of observers (for example, see Patent Document 1 (JP-A-2013-37260)).
As the virtual image display apparatus, for example, a technology of reducing luminance spots by forming respective output lights output from a panel forming image lights with principal rays at partially different output angles not in parallel to the optical axis (that is, forming non-uniform distributions by varying directionality) is known (see Patent Document 1).
As a configuration shown in Patent Document 1 or the like, for example, in the case where the directionality is varied and the principal rays of lights output from the peripheral part of the panel are directed outward from the panel, it may be necessary to increase the sizes of the respective optical systems including a light guide device and an eyepiece optical system provided at the downstream of the optical path of the panel.
Further, in the above described non-telecentric optical system in which the output angles of principal rays are partially different, it is highly likely that, when the position of the panel is moved along the optical axis direction, the aspect ratio of the virtual image finally visually recognized is changed to be different from the aspect ratio of the surface of image lights (hereinafter, also referred to as image surface) formed in the original position of the panel. Accordingly, for example, it may be difficult to adjust the imaging position within a desired range by moving the panel along the optical axis direction in response to correction of the manufacturing error, setting of the anticipated position of the virtual image, or the like.